I Recently Bought An 1989 Iroc-z Stock 305 Tpi. I Want To Know What Mods To Make That Will Give Me Horsepower Advantage Over Mustang 5.0..

Please Let Me Know How Much $ And How Much H.p. I Can Expect From Each Mod..

Thanks

 

hmm those 5.0's are quick how much did u spend on the 89?

 

$1800.00

 

what is the power of the 5.0?

the main thing is to get the TPI breathing better

start with gutting the air box under the air filters, then porting the upper intake plenum. you can remove the EGR "bumps" just inside the plenum, and then smooth out the transition from the plenum to the runners.

then i would go ahead and bump the timing up a little bit, i think stock is 6* and if you run 93 octane gas, you can get away with 10*.

i would also look into the exhaust. a good set of headers will help along with some kind of catback.

and after that...make sure you can hook up. the TPI (even the 305s) are torque monsters relative to the hp output. so get some lower control arms, a new torque arm mount (bound to be mushy) and some sticky tires.

i'd be willing to bet you'll give him a run for his money...assuming he is not cammed or built.

 

I have never understood why IROC 305's and 350's never performed better than they did. At the time I had a bone stock 89 stang GT and it would spank the 305 and run dead even with the 350.

 

Because of the TPI setup. It has an absolutely horrible top end, although the bottom end is very nice. That's the main advantage with a TPI, get some slicks and launch that bitch!

 

a 5.0L back in those days had a powerband up to 5500rpm, you could rev one up to 6000 and still have decent power and accel. My 89 LX 5.0L had no problem walking IROC's of that era whether they were 305's or 350's.

a 305 IROC TPI setup back then was done @ 4500rpm or so, revving it to 5000 + didn't do squat for power or accel.

Remember an IROC was also heavier than a 5.0L even though most magazines at the time gave it a handling edge over the 5.0L

A stick 5.0L with that 3.35 first gear practically catapulted the car off the line even when it had a 2.73 final drive ratio (even better with the optional 3.08) whereas the IROC with the 3.42 rear end but a 2.78 (I think) first gear didn't do much to help it off the line.

You'll have a lot of work to do to get that TPI IROC running with a 5.0L and keep in mind most of them now probably ain't stk. I wish you luck with your goal, you'll need it.

Tony

 

A 350 L98 IROC-Z should have no problems keeping up with a 5.0 5-speed. Also a G92 LB9 305 will keep up very close to a 5.0. Other variants (non-G92 LB9, L03, LG4, L69) will get beaten by the Ford however.

And IROCs DEFINETLY have a handling advantage over 5.0s.. IROCs were some of the best handling cars ever made, believe it or not. .92 gs on the skidpad, bone stock.

 

A 305 is not going to be very close to a 5.0. It is going to get walked. An L98 is going to have a hard time against a really well driven 5.0 5speed, and if the 5.0 is an LX my money is on the 5.0.

Yeah, I would say the IROC had the handling advantage over the 5.0, but would definetly not say they are some of the best handling cars in this day and age. Time marchs on. Gs pulled on the skidpad is largely a factor of how good the vehicle's tires are, and do very little to actually define the handling characteristics of a vehicle.

 

Go to www.tpis.com they have every thing for the tune ports.

 

The L98 makes more power than the 5.0 ford and even if the 5.0 has a 5-speed the stang will lose unless the $hit stain has aftermarket mods. the L89 will be close but the lx $hitstang is light and will most likely win over the L89 camaro.

 

Sorry you're wrong, the extra power the L98 makes over a 5.0L barely makes up for the extra weigh the IROC has over a 5.0L and unless the person in the stang can't drive to save his life the stang won't lose to a L98, stk vs. stk.

My 89 was a fully loaded LX when I had it, and I never lost to a guy driving an IROC back in the day and my friend had an 88 no options LX. It was a freak though with a K&N, LT's and a gear his car ran consistant 13.8 @ 101mph, no IROC's with the same mods back in the day would touch that.

Tony

 

Yeah, the L98 makes more power than the 5.0, but the 5.0 is lighter, and the L98 can only be had with any auto. I would bet with the parasitic loss of the auto that the L98 car is only going to be making alittle more at the wheels than the Mustang is. Another problem is the fact that the IROC auto has 4 forward gears, whereas the Stang has 5, and can better keep in its stock superior powerband.

As I stated, an L89 Camaro is in some sh*t against a 5.0 Stang, and a L98 has its work cut out for it.

 

First off, it's not an L89, It's an LB9. That's the 305 TPI motor.

A stock L98 thirdgen WILL run with a stock 5.0. I've seen it too many times to count. 88 - 90 L98s had no problems hitting a 14.4 at around 96. 91/92s can hit 14.3s. With tires a stock L98 car will break 13s. They will still trap horribly low however.

Whoever is saying an L98 car won't run with a 5.0, is in denial. Wake up and welcome to 1989.

To the original poster, the output of your vehicle depends on your transmission and options.

If you have an automatic, you had one option. 2.73 10 bolt, 195 HP/295 TQ.

If you have a stick, you're either a G92 car or you're not. Non-G92 had a 3.08 10 bolt, 220 HP/290 TQ. The G92 car had a 3.45 9 bolt Borg Warner rear, 230 HP/300 TQ.

If you have an M5/G92, all it will take is a headers back exhaust and you'll run with a 5.0. If you have an auto or the non-G92, look into gears and a stall for the auto.

 

The L98 I was refering to was my dad's 92 with 3.23:1 rear gear and a shift kit and he NEVER and I repeat NEVER lost to a stock stang. He even beat the saleens of the time. The Hp between the ford 5.0 and the L98 are close to the same but the L98 makes much more Torque.